This research proposal has been designed to identify the plasma membrane glycoproteins of mouse pachytene spermatocytes and round spermatids whose glycosylation involves dolichol-sugar intermediates. These experiments will utilize isolated populations of pachytene spermatocytes and round spermatids maintained in short-term in vitro culture. The specific objectives of this proposal include: 1) the characterization of mouse spermatogenic cells cultured in vitro to ensure adequate cell viability and metabolic activity; 2) analysis of the general kinetics of protein synthesis and protein glycosylation in vitro; 3) purification of plasma membranes from cultured pachytene spermatocytes and round spermatids; 4) identification of plasma membrane glycoproteins using two dimensional polyacrylamide gel electrophoresis; and 5) the analysis of plasma membrane glycoproteins after in vitro cell culture in the presence of tunicamycin.